January 25, 2016 - In the first segment of a three-part investigation, National Geographic travels to Prince William Sound in Alaska to meet with researchers who are studying the lingering effects of the catastrophic Exxon Valdez oil spill on the local orca population.

January 25, 2016 - In the first segment of a three-part investigation, National Geographic travels to Prince William Sound in Alaska to meet with researchers who are studying the lingering effects of the catastrophic Exxon Valdez oil spill on the local orca population.